1. Introduction

Vinyl playback is unusually resistant to being reduced to one number. A speed result says little about channel geometry; crosstalk says little about rotational stability; a low total harmonic distortion value does not reveal whether the platter is running at the correct mean speed. Conventional reports therefore present a collection of measurements. This is correct metrologically, but weak as a persistent comparative language: the reader must reconstruct the identity of a session from several pages, and two reports are easily compared selectively rather than systematically.

The purpose of the Vinyl Playback Fingerprint is to provide that comparative language without pretending that heterogeneous measurements are interchangeable. It preserves the original values and units, records whether each value is fit for comparison, maps an explicitly selected subset into a stable multidimensional representation, and binds the result to the measurement conditions and method version that produced it.

The method is intentionally not a universal sound-quality score. Vinyl playback is a coupled mechanical and electrical process, and a single ranking would conceal both causality and uncertainty. The VPF is instead a structured technical identity for a documented playback event. Its most useful question is not ‘Which turntable wins?’ but ‘How, where and with what confidence does this measurement differ from the reference measurement?’

The method supports three distinct applications: longitudinal observation of one setup, controlled comparison of playback systems, and controlled comparison of records or pressings. These applications share a data structure but do not share identical admissibility conditions. The distinction is central to DSR-VPF.

2. Scope and terminology

2.1 Vinyl Playback Fingerprint

A Vinyl Playback Fingerprint is a persistent, versioned data object that represents a defined set of objective measurements from one documented vinyl playback session, together with validity, uncertainty or repeatability, provenance and comparison metadata. It may be rendered as a radar chart, parallel-coordinate plot, deviation panel, table or another visual form. Changing the rendering does not create a new measurement, provided the underlying object and profile version remain unchanged.

2.2 Why ‘playback’ matters

The captured signal is not produced by the disc alone. It is shaped by the groove, stylus, cartridge, tonearm, turntable drive and bearing, alignment, tracking force, anti-skate, phono equalisation, electrical loading, gain structure, analogue-to-digital converter, clock and measurement environment. Unless those contributions are controlled or characterised, the correct object is a playback fingerprint rather than an intrinsic record fingerprint.

The shorter term Record Fingerprint may be used only for comparisons made through a declared reference chain whose relevant settings, calibration and repeatability are held constant. Even then, the result is an operational characterisation of the record under that reference method, not a metaphysical extraction of the record’s one true identity. Vinyl has enough personality already; the terminology does not need to add more.

2.3 Distinction from content-identification audio fingerprints

In information retrieval, an audio fingerprint normally means a compact content-based signature designed to identify a recording despite noise or transformation [1]. DSR-VPF has a different objective. It does not identify a song. It characterises measured playback behaviour. The term fingerprint is used because the stored multidimensional pattern is intended to be persistent, recognisable and comparable across documented sessions.

3. Existing measurement approaches and the methodological gap

Standards and specialist tools already cover important parts of vinyl measurement. IEC 60098 defines characteristics and agreed measurement methods for analogue audio disc records and reproducing equipment [2]. IEC 60386 addresses speed fluctuations, and its 1988 amendment introduced a preferred two-sigma method [3, 4]. Dr. Feickert Adjust+ and AnalogMagik provide specialised turntable and cartridge measurements [5, 6]. Industrial and academic projects have gone further into pressing analysis, spectral comparison and automated quality assurance [7, 8, 9].

DSR-VPF does not claim priority over any of those measurements, algorithms or graphical conventions. Its narrower contribution is to make a versioned, persistent multidimensional object - rather than an individual test result, a set-up screen, a spectrum or an anomaly alert - the explicit unit of cross-session comparison.

The structured public-documentation review was completed on 3 September 2026 and is summarised in Appendix C. It combined exact-phrase searches with conceptual searches across standards, scholarly repositories, product documentation, industrial quality-control descriptions and public patent web indexes.

No search can prove the absence of an earlier private, unpublished, non-indexed or differently described system. The originality statement in Section 15 is therefore bounded by the public record reviewed and is not a patentability opinion.

4. Measurement model and measurand

A digital capture of vinyl playback may be represented conceptually as a function of the record or test signal R, the mechanical playback chain P, the electrical and conversion chain C, the environment E, the session settings theta, and residual error epsilon. The analysis method A derives measurements from the observed waveform y(t).

The practical consequence is that every fingerprint must name its measurand and scope. A ‘turntable comparison’ is only meaningful when the record, cartridge-related variables and capture path are held sufficiently constant. A ‘pressing comparison’ is only meaningful when the playback and capture chain are held sufficiently constant. A ‘before/after alignment comparison’ requires the changed parameter to be named and other important variables to be controlled.

DSR-VPF therefore treats context as part of the measurement, not as decorative metadata. A fingerprint stripped of its test source, track, playback chain, capture format and method version may still be visually interesting, but it is not admissible for quantitative comparison.

5. The Fingerprint as a persistent data object

DSR-VPF separates measurement, interpretation and display. One compact representation is:

where id is an immutable fingerprint identifier; x is the vector of raw measurement values in their original units; z contains profile-defined display or comparison coordinates; q records quality and admissibility; u records uncertainty or repeatability information; p contains provenance and measurement context; and v identifies the method, metric-profile, projection and analysis versions.

This definition creates several safeguards. Raw values remain authoritative. A later change to a display scale cannot silently rewrite history. Invalid measurements remain visible as invalid rather than becoming zero. A comparison algorithm can determine whether two objects are compatible before calculating a distance. Finally, the same object can support more than one visual projection without implying that the data have changed.

• Multidimensional: the object contains measurements of different phenomena and units.
• Persistent: it is saved with an immutable identity and can be recalled independently of the live measurement screen.
• Versioned: method, metric-profile, normalisation, projection and application versions are explicit.
• Comparable: admissibility and compatibility rules are machine-readable.
• Auditable: raw values, validity, uncertainty and provenance can be inspected without relying on the shape of a graph.

6. VPF-Core-1K v1.0 metric profile

DSR-VPF may support several metric profiles. VPF-Core-1K v1.0 is the first fixed profile for a compact 1 kHz reference workflow. It is deliberately small enough to remain readable and broad enough to represent rotational, level, stereo and distortion behaviour. Version 1.0 fixes the six dimension identifiers and order, stored quantities, graphical transforms, display bounds, equal weights and default quality mapping. Signal-acquisition and analysis algorithms remain separately versioned so that later improvements do not silently alter historical objects.

6.1 Speed accuracy

For a reference tone whose recorded nominal frequency is f0 and measured fundamental is fhat, the signed speed error is:

For a disc nominally rotating at r0, the calculated rotational speed is rhat = r0(1 + es/100). The signed result must be retained because running fast and running slow are diagnostically different, even when the graphical projection uses absolute deviation.

6.2 Weighted wow and flutter

The fingerprint stores the reported value only together with the named weighting curve, detector or statistic, analysis bandwidth, carrier frequency and algorithm version. A value described merely as ‘wow and flutter’ is insufficient for strict comparison because different carriers, weightings and statistics can yield different numbers. The use of a 1 kHz carrier in VPF-Core-1K does not by itself establish conformity with IEC 60386 or another standard that may prescribe additional conditions. An implementation may claim a named standard method only when all relevant requirements are met; otherwise it must identify the result as a versioned DSR-VPF weighted estimate. Where a two-sigma or weighted-peak statistic is used, that choice is explicit [3, 4].

6.3 Channel balance

Channel balance is stored as a signed level difference, conventionally 20 log10(AL/AR), after the analysis has defined how amplitudes are estimated. The projection uses the magnitude of the imbalance, while the raw sign identifies which channel is higher.

6.4 Separation and directional crosstalk

The record stores left-to-right and right-to-left values separately. Because conventions differ, both the signed crosstalk ratio and the corresponding positive separation magnitude should be available. Average separation and directional asymmetry answer different questions and remain separate dimensions.

6.5 Distortion and harmonic profile

For a fundamental amplitude A1 and harmonics A2 to AK, THD may be calculated as the root-sum-square of harmonic amplitudes divided by the fundamental, expressed as a percentage. The fingerprint must declare K, bandwidth, windowing and aggregation method. Harmonic values H2-H5 may be retained as auxiliary dimensions even when the core projection uses a combined THD quantity.

6.6 Fixed diagnostic transforms

The profile uses the following transforms for its radar-deviation projection. All six dimensions have equal profile weight wi = 1.0. The bounds stabilise graphical meaning across sessions; they are not pass/fail tolerances, product specifications, audibility thresholds or claims of good and bad sound.

The profile may additionally store RPM range, raw speed-variation statistics, unweighted wow and flutter components, individual harmonics, residual-noise diagnostics and frame-validity measures. Auxiliary data enrich interpretation but do not automatically become radar axes. More spokes do not necessarily mean more knowledge; sometimes they just mean a busier spider.

7. Capture and extraction requirements

A VPF-compatible capture begins with a declared test source and track. Commercial test records can provide reference and channel-specific signals intended to examine cartridge and turntable behaviour; for example, Ortofon describes its Test Record as containing signals for analysing cartridge performance and its interaction with the tonearm and turntable [10]. DSR-VPF does not assume that any physical test record is perfect. Edition, side, track, condition and known calibration information must therefore be stored.

1. Document the complete playback chain: turntable, tonearm, cartridge/stylus, tracking force, anti-skate, alignment, azimuth, VTA/SRA where relevant, phono stage, loading, gain and power-supply configuration.
2. Document the capture chain: interface, analogue routing, sample rate, bit depth, clock source, channel mapping and gain settings.
3. Acquire with adequate headroom and without automatic gain control, sample-rate conversion or channel processing that is not declared.
4. Identify stable analysis regions and reject or flag frames affected by clicks, dropouts, mistracking, overload, loss of phase tracking or insufficient continuous tone.
5. Retain the analysis-method version and enough diagnostic data to explain why each dimension was admitted, downgraded or rejected.

The method does not require publication of copyrighted raw test-record audio. Derived measurements, short lawful visualisations, checksums and provenance can support auditability while respecting the rights attached to the source material.

8. Quality states, repeatability and uncertainty

The International Vocabulary of Metrology distinguishes repeatability as measurement precision under a stated set of repeatability conditions [11]. That idea is especially important for vinyl, where disc centring, groove contamination, stylus seating and transient defects can alter a capture. The Fingerprint therefore stores a quality state for every dimension rather than assuming that one successful export makes every number equally trustworthy.

A single valid capture may generate a fingerprint, but publication-grade controlled comparisons should state the repeat count and, where practical, use at least three valid captures per condition. This is a methodological recommendation rather than a conformance requirement in v1.0. Robust summaries such as the median and median absolute deviation may be preferable when occasional surface events remain possible. Mean and standard deviation may also be reported where the distribution and sample size justify them.

Repeatability is not the same as reproducibility. Reproducibility testing changes relevant conditions - for example operator, interface, location or reference deck - and asks how much additional variation appears. ISO 5725-2 provides a general framework for estimating repeatability and reproducibility of measurement methods, including preliminary use for methods not yet fully standardised [12]. DSR-VPF validation should use these principles without claiming standards compliance before the required study has been completed.

Where uncertainty cannot yet be expressed as a formal expanded uncertainty, the object should still preserve empirical repeatability intervals, valid-frame proportions and known systematic contributors. Honest partial uncertainty is more useful than a false aura of laboratory certainty.

9. Normalisation and graphical projection

The raw dimensions use incompatible units and directions. A graphical projection therefore requires a profile-defined transform. For a deviation-type metric, one general form is:

Here gi is a declared transformation, ti is the target or reference coordinate, and bi is a fixed display bound. Table 3 instantiates these terms for VPF-Core-1K v1.0. The bound is not estimated from whichever two fingerprints happen to be on screen. Data-dependent scaling would make shapes look comparable while changing their meaning from one comparison to the next.

The default diagnostic projection places the target or lowest defined deviation at the centre and increasing deviation outward. Separation, for which larger raw values are normally preferable, is converted into a separation-deficiency axis. Signed information remains available in labels and detail views. The display must expose raw values because radial distances are harder to compare accurately than values on a common linear scale.

Radar plots are useful as compact glyphs but can overemphasise polygon area, impose artificial relationships between neighbouring axes and become cluttered when many traces are overlaid. Polygon area must therefore not be used as a quality score, axis order is fixed by profile version, and detailed comparison must also provide aligned values or a delta table. DSR-VPF permits alternative projections where they improve readability, provided the projection identifier is stored.

10. Comparison rules

10.1 Compatibility before distance

Two fingerprints are compared quantitatively only when a compatibility predicate confirms that their profiles, source conditions and intended comparison mode are sufficiently aligned. A visually selectable overlay is not automatically a valid scientific comparison.

10.2 Missing-data-aware distance

When compatibility is satisfied, a weighted distance can summarise the separation between two normalised vectors. The distance must ignore unavailable or inadmissible dimensions rather than treating them as zero:

The associated comparison coverage is:

In VPF-Core-1K v1.0 every profile weight wi equals 1.0 and q follows Table 4. The numerical distance Dw lies between zero and one. It may be reported only when C is at least 2/3 and the relevant Class A, B or C compatibility requirements are met. Below that coverage the comparison is Class D descriptive only; at zero coverage no quantitative comparison exists.

A distance without coverage is incomplete, and distance is not a quality score. Every numerical comparison must also expose signed raw deltas, quality states and repeatability information. Agreement between methods or devices should be examined with techniques appropriate to the design; Bland and Altman’s work remains a useful warning that correlation alone does not demonstrate agreement [13].

11. Worked example using existing Groove Scope archive records

The following example uses two pre-profile Groove Scope 1 kHz records preserved in the Direct Sound Records public measurement archive [14, 15, 16]. Both source records remain drafts, were not acquired under the complete DSR-VPF protocol, and omit several setup fields. Their overlay is therefore Class D descriptive: it demonstrates data handling and visual logic, not an equipment ranking or a valid numerical fingerprint distance.

The example shows why a fingerprint needs more than a polygon. GS-2026-0002 has lower reported weighted wow and flutter but substantially larger mean speed error. GS-2026-0001 has stronger average separation, while GS-2026-0002 has smaller directional asymmetry. The second distortion result cannot be used. None of those facts supports a universal declaration that one complete system is superior. The useful outcome is a structured map of where the sessions differ and where the evidence is incomplete.

12. Intended applications

12.1 Longitudinal setup and maintenance

A baseline fingerprint can be repeated after cartridge alignment, tracking-force adjustment, anti-skate change, belt replacement, bearing service, power-supply change or stylus wear. The fingerprint helps prevent selective attention: an intervention that improves one metric while worsening another remains visible. It can also indicate when an apparent improvement is smaller than the method’s repeatability.

12.2 Cartridge and playback-system comparison

Under a common test source and controlled capture chain, fingerprints can summarise differences between cartridges, tonearms, turntables or phono configurations. The method does not remove the need for listening or explain subjective preference. It provides a repeatable technical companion to those observations.

12.3 Record, pressing and copy comparison

With a qualified reference chain, copies of the same release, test pressings, production runs, alternative compounds or records before and after cleaning can be compared. This application is the point at which the term Record Fingerprint becomes operationally defensible. Rotation-synchronous extensions may later preserve spatially recurring defects or noise patterns; Zaworski’s observation of coherence in rotation-length groove segments provides a relevant research precedent for that direction [7].

12.4 Manufacturing and archival quality assurance

The method could complement industrial master comparison and defect detection by supplying an open, compact summary of named metrics and their changes. It is not a replacement for full-side listening, spectral analysis, visual inspection or automated anomaly detection such as publicly described in Fonograph and AQA [8, 9].

12.5 Public datasets and machine-assisted analysis

A collection of versioned fingerprint objects can support search, clustering, longitudinal maintenance histories and future statistical studies. These uses become credible only when metadata and compatibility rules are preserved. Without them, a large catalogue becomes a large collection of attractive but incomparable shapes.

13. Limitations and failure modes

DSR-VPF is a measurement framework, not an escape hatch from the physical limitations of vinyl. Important limitations include:

• Test-source error. A reference tone’s cut frequency, eccentricity, wear and contamination can influence the result.
• Clock error. Frequency-derived speed estimates inherit error from the capture clock unless that clock is verified or corrected.
• Playback-chain confounding. Cartridge alignment, compliance, loading, gain, RIAA response, arm behaviour and stylus condition all contribute to the capture.
• Transient contamination. Clicks, mistracking, overload and dropouts can corrupt harmonic and channel estimates unless detected and handled.
• Position dependence. Outer-, middle- and inner-groove measurements are not automatically interchangeable.
• Environmental sensitivity. Structure-borne vibration, acoustic feedback and electrical noise can alter results.
• Visual bias. Radar area and axis adjacency can create an impression unsupported by the raw numbers.
• Profile dependence. A Fingerprint shape is meaningful only with its profile and normalisation version.
• Causal overreach. A changed fingerprint identifies a changed session; it does not uniquely identify the responsible component without controlled intervention.

The method must therefore be presented as technical observation rather than certification unless the complete measurement system has been validated for a certification purpose. It must not be used to manufacture league tables from incomparable user submissions.

14. Reference implementation and data stewardship

Groove Scope is designated as the first reference implementation of DSR-VPF. The existing Direct Sound Records Groove Scope Measurements archive already assigns immutable identifiers, preserves human-readable records and machine-readable JSON, records publication status, and anticipates separate application and analysis-method versions [14]. Its publication policy explicitly rejects silent rewriting of historical results and warns against league tables made from incomparable systems [17].

A DSR-VPF v1.0 JSON Schema and conforming example object accompany this publication. The archive schema can incorporate a fingerprint object containing method name, profile identifier, profile version, projection version, raw and transformed dimensions, quality states, repeatability or uncertainty, comparison class and provenance. Historical measurements may be reanalysed only by adding a new analysis or record version while preserving the original report and values.

Publishing the paper, schema and example data under stable identifiers supports the FAIR goals of making digital research objects findable, accessible, interoperable and reusable [18]. The DSR Technical Journal provides the human explanation; a preservation repository can provide a persistent citation; a versioned source repository provides the machine-readable contract; and Groove Scope supplies the reference implementation.

15. Originality and priority statement

The structured public-documentation review described in Appendix C was completed on 3 September 2026. It identified extensive prior work in individual vinyl measurements, multi-parameter setup, graphical display, statistical pressing analysis, spectral comparison and automated quality assurance [2, 3, 4, 5, 6, 7, 8, 9].

No reviewed source was found to explicitly define all of the following as one public method: (1) heterogeneous objective vinyl-playback metrics; (2) a persistent session-level data object; (3) a versioned normalisation or graphical profile; (4) per-dimension validity, admissibility and uncertainty or repeatability; and (5) explicit cross-session comparison rules in which that object is the unit of comparison.

This statement does not claim invention of the underlying measurements, radar charts, content-identification audio fingerprints, record-quality research, spectral comparison or automated quality assurance. It is a bounded priority and attribution statement about their integration and formal use in DSR-VPF. It is not a legal opinion on patent novelty, inventiveness, freedom to operate or trademark availability, and it should be revised if an earlier qualifying public source is identified.

16. Validation and revision programme

Publication version 1.0 freezes the DSR-VPF object architecture and VPF-Core-1K profile so that implementations and datasets have a stable reference. It does not imply that the complete measurement system is a calibrated standard or that inter-laboratory repeatability and reproducibility have already been established.

1. Specify and version each supported test signal, analysis window, estimator, bandwidth, weighting, sign convention and automated quality rule.
2. Characterise source and capture-clock error, including a traceable or independently verified frequency reference where practical.
3. Measure within-session repeatability across multiple valid captures and define rules for robust aggregation.
4. Test intermediate precision by varying day, operator, record reseating and other realistic conditions.
5. Assess inter-device and inter-interface reproducibility where Groove Scope supports more than one capture configuration.
6. Validate sensitivity through controlled interventions expected to affect specific dimensions, while checking for collateral changes.
7. Review the v1.0 display bounds against empirical distributions and intended use; any altered transform or bound must receive a new profile version and must not rewrite v1.0 objects.
8. Evaluate agreement between software versions or reference systems with delta analysis and, where suitable, Bland-Altman methods rather than correlation alone [13].
9. Publish validation datasets, schema revisions, worked examples, change policy and known limitations under stable version identifiers.

Validation may lead to more than one profile. A compact consumer-facing 1 kHz profile, a laboratory reference profile and a pressing-comparison profile need not use identical dimensions. What remains common is the DSR-VPF object model: raw data, validity, uncertainty, provenance, versioning and controlled comparison. Later profiles and method revisions must coexist with, rather than silently mutate, version 1.0.

17. Conclusion

The Vinyl Playback Fingerprint addresses a practical gap between isolated measurement reports and meaningful longitudinal or comparative analysis. Its contribution is not a new speed test, distortion formula or chart type. It is the definition of a persistent, versioned and auditable multidimensional object in which raw vinyl-playback measurements, quality states, uncertainty and provenance remain inseparable from the graphical identity used for comparison.

By separating the measurement object from its visual projection, refusing to convert unreliable data into decorative certainty, and requiring compatibility before distance, DSR-VPF can serve enthusiasts, reviewers, engineers, record labels and pressing plants without collapsing complex analogue behaviour into a simplistic score.

This publication establishes DSR-VPF v1.0 and VPF-Core-1K v1.0 as stable public references. Groove Scope is designated as the first reference implementation, and the Direct Sound Records archive provides a natural public home for versioned examples. The next phase is empirical validation and implementation; any substantive change will be published under a new version rather than applied retroactively.

Declarations

Competing interests: The author is the developer of Groove Scope and the creator of the DSR Vinyl Playback Fingerprint Method. Direct Sound Records publishes the associated measurement archive.

Funding: No external funding was received for this work.

Author contributions: Conceptualisation, methodology, software direction, data curation, visualisation, writing and final approval: Michelangelo Canonico.

Data availability: The illustrative source records are publicly available in the Direct Sound Records Groove Scope Measurements repository [14, 15, 16]. The publication package includes the DSR-VPF v1.0 JSON Schema, the fixed VPF-Core-1K profile and a conforming example object.

Method status: DSR-VPF v1.0 is a published technical method specification. It is not an international standard, accredited test method or certification procedure. Empirical validation remains ongoing and later revisions must be versioned.

Licence: This paper and accompanying open specification are released under Creative Commons Attribution 4.0 International (CC BY 4.0).

Generative-AI assistance: Generative AI tools were used for editorial assistance, literature discovery and document preparation under the author’s supervision. All measurements, scientific claims, interpretations and final responsibility remain with the author.

References

1. Cano, P., Batlle, E., Kalker, T. and Haitsma, J. (2005). A Review of Audio Fingerprinting. Journal of VLSI Signal Processing Systems, 41, 271-284. Source
2. International Electrotechnical Commission. IEC 60098:2020: Analogue audio disk records and reproducing equipment. Source
3. International Electrotechnical Commission. IEC 60386:1972: Method of measurement of speed fluctuations in sound recording and reproducing equipment. Source
4. International Electrotechnical Commission. IEC 60386:1972/AMD1:1988: Amendment 1 - new preferred two-sigma method. Source
5. Dr. Feickert Analogue / ProgTec GmbH. (2008). Adjust+: Azimuth/Crosstalk Instructions and Whys. Revision 17 September 2008. Source
6. AnalogMagik. AnalogMagik Version 2 Cartridge Setup Software - official product and test-function documentation. Source
7. Zaworski, C. (2022). The optimization of a modern day record press. Master’s thesis, University of Waterloo. Handle 10012/17874. Source
8. Stamper Discs. Fonograph - objective audio comparison. Public technical description. Source
9. Daley, S. (2023). PRP Announces New Audio Quality Assurance System. Precision Record Pressing, 14 September 2023. Source
10. Ortofon. Ortofon Test Record - official product and use description. Source
11. Joint Committee for Guides in Metrology. JCGM 200:2012: International Vocabulary of Metrology - Basic and general concepts and associated terms, 3rd edition. Source
12. International Organization for Standardization. ISO 5725-2:2025: Accuracy (trueness and precision) of measurement methods and results - Part 2. Source
13. Bland, J. M. and Altman, D. G. (1986). Statistical methods for assessing agreement between two methods of clinical measurement. The Lancet, 1(8476), 307-310. PMID 2868172. Source
14. Canonico, M. and Direct Sound Records. Groove Scope Measurements - public measurement archive. Source
15. Direct Sound Records. GS-2026-0001: Rega P3 / RB330 / Audio-Technica AT-OC9XML / Audio Research SP20 - 1 kHz Reference Check. Source
16. Direct Sound Records. GS-2026-0002: Ortofon OM10 / Thorens TD160 Super / SME III - 1 kHz Reference Check. Source
17. Direct Sound Records. Groove Scope Measurements: Publication and measurement policy. Source
18. Wilkinson, M. D. et al. (2016). The FAIR Guiding Principles for scientific data management and stewardship. Scientific Data, 3, 160018. Source

Appendix A. Minimum metadata required by DSR-VPF v1.0

A conforming DSR-VPF v1.0 object must provide, or explicitly mark as unavailable where the schema permits, the following information:

• Immutable fingerprint and measurement identifiers
• Fingerprint method, profile, normalisation/projection and analysis versions
• Publication status and record version
• Measurement date, local time and time zone
• Comparison class and declared measurand
• Turntable, tonearm, cartridge/stylus and power supply
• Tracking force, anti-skate, alignment, azimuth and VTA/SRA where applicable
• Phono stage, gain, loading and relevant filters
• Test record, edition, side, track, condition and nominal signal
• Audio interface, routing, gain, sample rate, bit depth and clock information
• Per-dimension raw values, units, sign convention and estimator
• Per-dimension quality state, admissibility weight, valid-frame information and repeatability/uncertainty
• Normalised coordinates and fixed profile transforms/bounds
• Known limitations, interventions and environmental notes
• Source report, checksums, licence and provenance

Appendix B. Example machine-readable DSR-VPF v1.0 object

The example re-expresses selected values from GS-2026-0001 through the fixed VPF-Core-1K v1.0 display transforms. Because the source session predates the complete protocol and remains a draft archive record, it is eligible only for descriptive Class D use.

{
  "fingerprint_id": "VPF-2026-0001",
  "measurement_id": "GS-2026-0001",
  "method": "DSR-VPF",
  "method_version": "1.0",
  "profile": "VPF-Core-1K",
  "profile_version": "1.0",
  "projection": "radar-deviation-1.0",
  "comparison_class_eligibility": ["D"],
  "dimensions": [
    {"id":"speed_error","raw_value":-0.71,"unit":"%",
     "quality":"primary_valid","q":1.0,"z":0.2367},
    {"id":"weighted_wow_flutter","raw_value":0.045,"unit":"%",
     "quality":"primary_valid","q":1.0,"z":0.1500},
    {"id":"channel_balance","raw_value":-0.63,"unit":"dB",
     "quality":"diagnostic_only","q":0.0,"z":0.2100},
    {"id":"separation_deficiency","raw_value":30.4,"unit":"dB separation",
     "quality":"supporting_valid","q":0.5,"z":0.3200},
    {"id":"crosstalk_asymmetry","raw_value":5.4,"unit":"dB",
     "quality":"supporting_valid","q":0.5,"z":0.4500},
    {"id":"thd","raw_value":0.31,"unit":"%",
     "quality":"supporting_valid","q":0.5,"z":0.1033}
  ],
  "provenance": {
    "source_record":"GS-2026-0001",
    "source_record_status":"draft",
    "status":"illustrative_pre_profile_reanalysis",
    "note":"Not acquired under the complete DSR-VPF v1.0 protocol."
  }
}

Appendix C. Public-documentation search protocol

The priority statement in Section 15 is based on a structured review of public documentation completed on 3 September 2026. The review was designed to find systems that combined the same defining elements as DSR-VPF, not merely systems that used the words “audio fingerprint” or displayed individual vinyl measurements.

• Sources reviewed included IEC and ISO catalogues, scholarly and university repositories, manufacturer and product documentation, pressing-plant quality-control descriptions, public web patent indexes and the existing Direct Sound Records archive.
• Exact-phrase searches included “vinyl playback fingerprint”, “record playback fingerprint”, “vinyl fingerprint” with measurement terms, and combinations of turntable, cartridge, multidimensional, persistent, graphical, comparison and fingerprint.
• Conceptual searches covered multi-parameter vinyl measurement, radar or spider plots, stored measurement profiles, record-pressing quality metrics, spectral comparison, automated vinyl quality assurance and rotation-synchronous analysis.
• A potential anticipation had to combine heterogeneous objective vinyl-playback metrics, a persistent session-level object, a versioned graphical or normalisation profile, per-dimension validity or uncertainty, and explicit cross-session comparison rules.
• Located precedents were retained in the review even when they did not satisfy all criteria; Table 1 states the relevant boundary rather than dismissing their contribution.